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1991 BMW 525i Question: BMW 525i European Spec

 

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Nailz127, Rochester, NY, August 17, 2010, 21:06
 Rookie

I bought the car about three week ago and it ran fine for about two days. I recently took the vehicle to the dealer where I bought it and he tells me the car is fine. The problem I am facing is that the car won't start. I turn the key and all I hear is a click sometime just one click. Other times I hear nothing. Sometime she will start but the engine cranks for a few seconds. The mechanic has check the voltage on the battery and the alternator. I just had a alternator replaced today. The battery was replaced about three days ago. She starts up just fine when she is jumped other than that nothing. I have a radio installed in the car just a radio could it be draining the battery. Everything else in the car works fine lights, radio, a/c, dash lights, all the above. I just want the car to start and when I turn it off to turn back on. Any help you have for me...

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  • Answer #1

    patrick mannion from Greg Solow's Engine Room, August 17, 2010, 21:59
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     Master

    When the car won't start put a voltmeter across the battery and check its voltage it should be 12.6 volts at rest. It could be a bad or unsecured battery ground cable between the battery and chassis or chassis and engine. Turn on the ignition switch to the on but not run position do you see an icon on the instrument panel representing a battery, if you do not see this battery icon the alternator is not seeing power to allow it to charge. Start the engine does the battery icon go out. A more complex but good diagnostic test is checking "voltage drop" on the battery ground and power cables. You can find a video on how to do a voltage drop test on youtube. Put a volt meter across the battery terminals with the engine off, at rest the battery voltage should be 12.6 volts if the battery is fully charged. Now get a friend to start the car while you watch the voltmeter, the voltage reading across the battery should read approximately 14.6 volts if the alternator is charging correctly.
    You may have some sort of battery draw that needs to be isolated and illuminated. You would need an amp meter disconnect one cable of the battery put your Amp meter in series with the battery cable that has been removed. Note the draw say for example 15 Amps, with the keys out of the ignition, doors closed driver's window down, start removing the fuse links and fuses one at a time until the voltage draw goes away to zero (or near zero). It is that circuit that is causing the electrical draw, then look at a wiring diagram, see what consumers are on that circuit and start to isolate each circuit to see which is the culprit. Modern cars have lots of computers and electronics that need constant battery even with the key off so parasitic draw of .2 Amps may be normal.

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    Visitor, August 23, 2010, 03:31

    ok I did the voltage drop and nothing everything seems to still work as normal...After installing the brand new alternator the voltmeter read 13.6 that woudl be after with everything running in the car...Now I thought the car woudl have been good at that point the mechanic told me to just go on a long drive to charge the battery back to substaintial power...I drove the vehicle for about an hour and a half and still nothing when I shut the car off and back on I still hear a click...Would the radio have anything to do with the draining of the battery in the car...When I put the face plate on the car and run the radio the lights in the dash dim a bit...When trying to run the radio and headlights at the same time the radio cuts off and on...Now the car sits in a certified BMW shop getting repaired I feel as though if I take the car again she will do the same thing with not starting up...Any Help I woudl consider...Hwo woudl I check to see if my battery ground cable is bad, loose, or unsecured?

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    Nailz127, August 24, 2010, 06:27
     Rookie

    Alright so like u said it was some loose wires going from the engine to the chassis that were causing the alternator to not carry the electricity load so got that fixed up and now she runs great but man it sure does cost a lot to have someone tell you that there are some loose wires in the vehicle...I also had the battery charged and she should run great with no problems now...Thanks man

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